GB288810A - Improvements in and relating to sound reproducing instruments, such, for example, as loud speakers - Google Patents

Abstract

288,810. Custerson, R. April 6, 1927. Loud-speakers ; magnetic instruments.-Relates to sound-reproducing instruments of the type in which a diaphragm is operated by a reed and more particularly to loud-speakers having a conical diaphragm of the kind described in Specification 268, 160 and consists in mounting the reed so that its length free to vibrate decreases as the amplitude of vibration increases thereby avoiding uneven response to various frequencies. A shaped reed. Fig. 1, may be employed having narrow arms 5, 6, an enlarged central portion 7 and enlarged end portions 8, 9. Soft washers 10 - - 13 and hard conical washers 14 - - 17 of slightly smaller diameter are provided on each side of the ends 8, 9 of the reed, as shown in Fig. 2, the whole being secured by screws 18, 19 to a case 20. In modified arrangements, the conical washers 14 - - 17 may be replaced by based flat washers of graduated diameters or conical soft washers clamped between hard washers may be used. The reed may have more than two arms, and may operate as a balanced armature if desired. The complete loud-speaker is enclosed in a cabinet the back of which is formed of a number of slots 22 - - 26 around which a strip of cloth 27 is threaded as shown in Fig. 4. In some cases, the whole of the back of the cabinet may be covered with a heavy semi-flexible material, such as baize, in which case the slots may be omitted.